| PURPOSE Our research aims to study the relationship between HO system and learning and memory, as well as the functions of HO during the course of neurodegeneration and acute brain i schemialreperfusion injury. METHODS I. Approach of medication: Intracerebroventricular (ICV) injection. 2. Learning and memory test: Passive avoidance reaction (by method of step through and step down), spatial discrimination test (by method of Morris water maze). 3. Determination of HO expressing level: By techniques of RT-PCR, Western Blot, and immunohistochernistry. 4. Monitoring of apoptosis: by method of TUNEL. 5. Other techniques employed in this research: radio-immunity assay, inductively coupled plasma atomic emission spectrometry (ICP-AES), silver impregnation staining, biochemistry assay. CONTENTS 1. Investigating the effects of changing HO and/or NOS activity by ICV injection on locomotive activity, passive avoidance reaction, and spatial learning and memory of mice, as well as the effect of praxiology training on HO expressing level. 2. Studying the effect of neurodegeneration induced by ICV injection of different concentrations of Aid3 and following drug therapy on passive avoidance reaction of mice; exploring what role HO (HO-i) is playing during the course of neurodegeneration induced by aluminum. 3. Doing research into the influence of different pretreatments that alter activity of HO (HO-i) on the prognosis of acute incomplete forebrain ischemialreperfusion injury. RESULTS 1. ICV injection of ZnPPIX and/or L-NNA inhibited activities of HO and/or NOS obviously: activities of HO and NOS were suppressed 43% and 42% with the concentration of O.OSmmol/L(P<0.O 1), and 63% and 56% with the concentration of 0.1 Smmol/L, respectively(P < 0.01). ICV injection of hemin in the concentration of 0.OSmmol/L and 0.1 Smmol/L induced HO activity to rise about 1 6%(P < 0.05) and 28%(P<0.0 1). Among all treated groups, there were no obvious differences in locomotive activity, step through latency, step downlatency, number of errors, time of electric shock, and time of staying on platform(P> 0.05). As for the performance in the Morris maze, platform-searching time showed no differences in the last clued navigation(P> 0.05), but the time was prolonged in groups of ICV injection of Hemin, ZnPPIX and/or L-NNA in the last oriented(placed) navigation. The times of crossing the region where having placed platform also lessened in those groups in spatial searching tests(P<0.01 or P<0.05). HO activities raised 21% in brains of mice which had received training of step-through, step-down and Morris maze(P<0.05). The results of RT-PCR showed that there was no difference in HO-2 expressing level between dark-breed and praxiology-trained animals(P >0.05); but HO-i expressing level sig iificantly decreased in dark-breed group(P<0.01), and remarkably raised in praxiology-trained group(P< 0.01), compared with control. Similar results in these two groups were also obtained by Western Blot method. 2. There was no difference in locomotive activity among all groups of animal I month after ICV injection of AIC13(P> 0.05), but the performance in step-through and step-down both was infe... |
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